Patent Literature 1 discloses a semiconductor light-emitting device. The semiconductor light-emitting device has a semiconductor stack, which lowers threshold current density for laser oscillation and reduces the occurrence of kink, and the semiconductor light-emitting device of a surface-emitting semiconductor laser has a fixed polarization plane of laser oscillation, and reduces a variation in the oscillation plane.
Patent Literature 2 discloses a light-emitting diode device, a semiconductor laser device, a photosensitive device and a transistor which are made of group III nitride semiconductors. These group III nitride semiconductor devices include an AlGaN layer having a high Al composition and a high carrier concentration. The growth of the AlGaN layer is carried out so as to enhance the surface diffusion of Al atoms, although the surface diffusion is small in AlGaN growth. The AlGaN layer with a high Al composition and a high carrier concentration can be grown on the surface of a GaN substrate that tilts by an angle of 1 degree to 20 degrees.